Octane for mountains

[PlaynInPeoria]

We are leaving FrI day after next from Peoria to ride 1000 miles in Colorado. My 10 did fine, wondering how the C14 will tolerate the altitude.

Someone just told me you can't get high octane out there. Is he full of crap? I plan on still running 93 if possible. I've ridden on many, many road trips, just never at altitude on a C14.

Anyone with experience in this area?

Thanks.

[gPink]

I have had zero problems at altitude. When I had to buy 85 I bought only what I needed and topped off with higher octane as soon as available.

[Gigantor]

The CV carbs on your Connie will help you do the best that can
be expected. Nothing makes up for the lose of oxygen so you will
lose some power.

Make sure you have a new air filter though

[C14lvr]

Just got back from touring all over the Colorado mountains, as high as 14,000'.
Yes, it is true that many stations may only have 85 octane out there.

I've had no problems riding there on my 2011.
You may notice some power reduction if your above 10,000 feet, but not a big deal.
ECU/ FI bikes deal with it fine. (Much better than a carb'd bike does.)

I didn't run mine in ECO mode when I was above 10,000 feet.

Let's face it, there are lots of places out there where you won't have any choice but to use 85.

[angelo]

I too just got back from out west.  You will find stations where nothing in the 90s is available.  Don't think I ever came across one where 85 was the only option.  Seems like there was always at least an 87 option - if not 89.  If needed, though, I would have bought it to get somewhere no problem.  I got better mileage riding aggressively up there than slabbing over on 93 octane, btw...  Altitude made a difference for sure.  Same way your Toyota runs 87 suddenly does fine on the 85 up there. 

side note -  noticed  a lot more "pure" gas options than back home too.

[Rick Hall]

We are leaving FrI day after next from Peoria to ride 1000 miles in Colorado. My 10 did fine, wondering how the C14 will tolerate the altitude.

Someone just told me you can't get high octane out there. Is he full of crap? I plan on still running 93 if possible. I've ridden on many, many road trips, just never at altitude on a C14.

Anyone with experience in this area?

Thanks.

Having lived here (7500') for 15 years... You can get premium (and mid-grade) with no problems. However the octane rating is two points less than you may be used to, once you reach gas stations 'at elevation' (approx 4500') that is. Regular is 85 octane, you're used to 87?

There is no air up here (duh), therefore you can't get a sea-level charge of air in the cylinders. Or less chance for detonation/knocking.

Buy premium if your bike calls for it, keep in mind the octane number will be two points less. It's NOT a problem.

Rick

PS: If your engine is turbo-normalized, run recommended octane.

[Rhino]

+1 What Rick said!

Because the air at high altitude is at lower pressure, you have lower pressure in you cylinders and therefor do not need as high an octane as you would at sea level. As a result, premium at high altitude in Colorado is typically 89 and works fine in you C14 at high altitude.

[jwh20]

+1 What Rick said!

Because the air at high altitude is at lower pressure, you have lower pressure in you cylinders and therefor do not need as high an octane as you would at sea level. As a result, premium at high altitude in Colorado is typically 89 and works fine in you C14 at high altitude.

And even though the engine makes less HP, you can still go just as fast since the air is thinner and offers less resistance!

[VirginiaJim]

What's not to like?

[Diamondhead]

10% power loss for every. 2000 ft in elevation

[AlbertaDoug]

10% power loss for every. 2000 ft in elevation

Well I was at 7239' on Sunday I'm guessing that I was down a bit. It was also 36* do you think tha cold air gave me a few of those lost horses back?

[Rhino]

Well I was at 7239' on Sunday I'm guessing that I was down a bit. It was also 36* do you think tha cold air gave me a few of those lost horses back?

Yes, cool dry air helps but doesn't completely compensate for altitude.

[Rhino]

And even though the engine makes less HP, you can still go just as fast since the air is thinner and offers less resistance!

Only if you have a fresh battery in your FOB 

[Stasch]

Couple times we had to run 85 octane in carbureted DS bikes (2 350's and 1 400) at the Cortez National.

I normally run 91 in mine due to a higher compression piston.

I felt the bike actually ran a bit better on 85 when in high altitude.

Nothing scientific to back that up, just my impression.

[gggGary]

 "oil thread warning" 

Lower octane fuel "in general" has a higher energy content.

To quickly get your head around this;
Diesel, designed to "self combust" ie it's  "very low octane" has about 11% more energy content than gasoline.
The lighter the fuel, the lower the energy content.  Alcohol is light but has high octane, And lower energy content.  Pure alcohol spark ignition engines can run 16 or 17 to 1 compression ratios but the alcohol has about half the energy content of gasoline.
In general you will get better fuel mileage at higher elevation, in addition to thin air I think the ups and downs actually improve mileage. 

Mmm Colorado in July on the Connie, what could be finer?

[VirginiaJim]

Carolina in the morning?

[martin_14]

"oil thread warning" 

Lower octane fuel "in general" has a higher energy content.

To quickly get your head around this;
Diesel, designed to "self combust" ie it's  "very low octane" has about 11% more energy content than gasoline.
The lighter the fuel, the lower the energy content.  Alcohol is light but has high octane, And lower energy content.  Pure alcohol spark ignition engines can run 16 or 17 to 1 compression ratios but the alcohol has about half the energy content of gasoline.
In general you will get better fuel mileage at higher elevation, in addition to thin air I think the ups and downs actually improve mileage. 

Mmm Colorado in July on the Connie, what could be finer?

All true, but not very helpful. You can put plutonium in the engine, if it can't get the most off it, it doesn't matter. The lower octane fuel does have more energy content, but this engine is designed with more compression ratio. Conversely, an engine designed with low compression ratio will not get extra power by using higher octane fuel.
But regarding mileage, I never thought about how it would be affected by the octane. Mmm... food for thought. That hurts.

[gggGary]

Yet it seems to have stirred your BC's at least a bit...
Yes you need to run what your motor needs, is designed for, no argument.  Just highlighting the maybe not so obvious reverse ratio of energy vs octane.
To recap; in thinner air your peak cylinder pressure will be lower, effectively the same as lower compression.  So lower octane should be fine, as a benefit you will likely see higher mileage. That may also be due to reduced RH twisting; impressive scenery, rocks in the road, fewer passing opportunities, and the serious consequences of a missed apex in the mountains!
While looking for confirmation (hopefully  ) of my thoughts on this I ran into a guy that did testing with an older civic and he was able to document to his satisfaction better fuel mileage with low vs high octane gas.  The Prius tech forum also found that correlation and they are crazy about MPG. For whatever reason Prius tend to run poorly on high octane fuel.
Octane vs energy is very complex and fuel formulation is all over the board these days.  I have a feeling that petro engineers are very good at meeting fuel specs while using what ever part of the cracking process is plentiful. 

All true, but not very helpful. You can put plutonium in the engine, if it can't get the most off it, it doesn't matter. The lower octane fuel does have more energy content, but this engine is designed with more compression ratio. Conversely, an engine designed with low compression ratio will not get extra power by using higher octane fuel.
But regarding mileage, I never thought about how it would be affected by the octane. Mmm... food for thought. That hurts.

[Rhino]

"oil thread warning" 

Lower octane fuel "in general" has a higher energy content.

To quickly get your head around this;
Diesel, designed to "self combust" ie it's  "very low octane" has about 11% more energy content than gasoline.
The lighter the fuel, the lower the energy content.  Alcohol is light but has high octane, And lower energy content.  Pure alcohol spark ignition engines can run 16 or 17 to 1 compression ratios but the alcohol has about half the energy content of gasoline.
In general you will get better fuel mileage at higher elevation, in addition to thin air I think the ups and downs actually improve mileage. 

Mmm Colorado in July on the Connie, what could be finer?

Headed back there this Saturday to ride with my son. I will not be on the Connie but will be on my old Valkyrie and it will be fine!

[PlaynInPeoria]

Mmm Colorado in July on the Connie, what could be finer?

Nothing?

3k in California last year didn't suck though.  Both trips are "bring all your gear" trips.  Hot as hell going from IL to CO I suspect, then cold and rainy at various points in the mountains.  Pike's Peak will be a new and cool thing.  This is my 4trh bike trip out there, I am taking 4 friends who have never been.  Going cool places I have been to show them, then other places I have always wanted to go.

Wonder how 40 miles of dirt road coming into Crested Butte from the west will go?